Protraction and retraction of the scapula are movements that occur along the thoracic wall and are essential for upper limb function and overall shoulder mechanics. Protraction involves the scapula moving away from the spine and around the rib cage, as you’d see when reaching forward or pushing something away. The primary muscle responsible for this is the serratus anterior, which pulls the scapula anteriorly and laterally. Retraction is the opposite movement—drawing the scapulae back toward the

Flexion and extension are two key movements performed at the knee joint. Knee flexion occurs when a person bends the leg, bringing the heel closer to the back of the thigh. It reduces the angle between the femur and tibia. The range of knee flexion varies according to the position of the hip and whether the movement is active or passive. In contrast, knee extension happens when a person straightens the leg, moving the heel away from the thigh. This increases the angle between the femur and tibia